1. Field of the Invention
The invention relates to a method for data reception in wireless vehicle-to-surroundings communication (C2X), in particular mobile vehicle-to-surroundings communication or vehicle-to-vehicle communication (C2C) as a special case of C2X communication, in a communication system of a vehicle with a plurality of control devices in which a receiving control device receives data from objects from the surroundings of the vehicle and in which, during the reception of the data, in at least one control device, but preferably in a plurality of control devices of the vehicle, a communication stack is processed, and also a correspondingly configured communication system of the vehicle.
2. Related Art
A vehicle communication system of this type usually consists of a plurality of control devices which perform different functions. In the vehicle, the data physically received by one or more antennas with one or more allocated receivers (or combined transmitters and receivers) are further processed by the one control device or the plurality of control devices of the communication system. Typically, one of the control devices, which is also referred to in the context of this application as a receiving control device, will contain the transmitting and receiving part and parts of the communication stack to be processed, which will be explained in somewhat more detail below. At least one control device is then provided for the actual application, for example a driver assistance function. Further parts of the communication stack, for example with the facility layer, may also be located in still further, different control devices of the vehicle.
The reception process and the tasks of the control devices performed therein are controlled by the so-called communication stack. The C2X communication stack or the associated C2X communication protocol describes, with reference to the OSI model, the tasks which are performed in mobile C2X communication. This communication stack is largely standardized in Europe by an industry cooperation of the C2C Communication Consortium (C2C-CC) and the ETSI and/or the CEN. In the USA, the standardization is carried out by e.g. IEEE, SAE, etc. The tasks to be carried out by the communication stack may, in particular, be the (physical) data reception, the routing of the data, the processing of the data between the reception and the application or the provision of data in the vehicle. These tasks are performed according to the specifications in different layers of the OSI model.
In C2X communication, data are exchanged between the vehicle (C) and objects in its surroundings (X). The objects in the surroundings may be permanently installed transmitting units by the side of the road, referred to as Road Side Units (RSU), other vehicles participating in the traffic or standing idle, or pedestrians equipped with corresponding transmitters and/or receivers. The exchanged data perform different functions, for example a protection, warning and/or information function, and can also be used by a driver assistance system.
In C2X communication, depending on the traffic density or density of transmitters participating in the C2X communication, the exchange of large data volumes may occur, so that the bandwidth available in the physical radio band for the communication is heavily loaded. It is known that bandwidth is a limiting factor in the transmission and/or reception of data. Exhaustive use of the bandwidth can result in time delays to the point of a breakdown of the communication network. However, in the case of the safety-related applications of the mobile C2X communication, the data exchange can be extremely time-critical, since the traffic situation of a moving vehicle, where appropriate, changes quickly and a warning is intended to be given in good time before a dangerous situation. At the same time, the dangerous situation itself often changes also. It is therefore necessary for the communication system of a vehicle to record and further process the information exchanged in the C2X communication quickly. The volume of information represents a major problem here.
US 2003/0139881 A1 shows a method for operating a pre-crash sensing system for a vehicle by means of C2X communication, which, following a first check, allows communication with specific objects only. To do this, a pre-crash sensing system determines the proximity or distance between the one own vehicle and the other vehicle serving as a possible communication partner. If the vehicles are located in their mutual field of view, a key is exchanged and communication is started. As a result, only vehicles which could potentially represent a danger to one another communicate with one another. The data volume is thereby reduced compared with a communication solution in which all vehicles in a predefined surrounding area would communicate with one another. However, it is disadvantageous that, due to the checking of a hazardous situation and subsequent key exchange, the communication becomes more complex and the establishment of communication takes longer. In the case of a critical situation, this can result in problematic delays. This type of establishment of communication also results in an increase in the exchanged data volume, particularly also in time-critical dangerous situations. This partially cancels out the described advantage in the selection of information and can, for its part, result in time delays.
WO 2006/015747 A1 shows a preventive protective system with which the features from the multiplicity of input variables of the safety sensor system relevant to the safety of the motor vehicle are filtered out. The preventive protective system of the motor vehicle acts preventively in that the safety sensor system is controlled depending on preselected features. It is proposed, for example, to allocate a specific weighting, in terms of criticality, to features indicating a frontal impact. This system accordingly describes a specific filtering for a specific dangerous situation. However, no distinction is made here as to whether a danger could or could not arise at all from a detected object. Moreover, the features must be defined in advance, so that this case is not appropriately applicable to a complex and variable C2X communication with many different participants.
In mobile C2X communication, extremely large data volumes can occur, which must be processed quickly and completely, as they are otherwise worthless. There is the additional hindrance that not every control device of the communication system can process all data. In particular, safety-related data should only be processed by control devices which have a low probability of failure. The probability of failure is indicated here by the so-called ASI level, which is defined in detail in ISO 26262.